This invention relates to centering mechanisms; and more particularly to a centering mechanism for centering the disk recording medium over the spindle of a rotating disk storage system. Even more particularly, this invention relates to a centering mechanism that uses resilient fingers; is self cleaning; and limits impact forces during insertion.
Disk recording media are used in the computer industry for storage of large amounts of data. The recording media may contain millions or billions of bytes of data which are accessible to the computer by means of a transducer which scans the data as it rotates at high speed relative to the transducer. The recording medium may be a ferromagnetic material having magnetic characteristics which make it suitable for reading or it may have optical characteristics which make it suitable for reading or it may have still other characteristics. In most instances the medium itself is somewhat fragile and although it typically rotates at high speed, the medium itself is not attached to a spindle, but instead is attached to and supported by a centerpiece which is then mounted on the spindle or other spinner mechanism of a motor.
The centerpiece must be accurately centered because data reading and writing transducers rely on the concentricity of the data tracks. While adjustments of the transducer are made by servos, the data tracks are centered at the geometric center of a centerpiece which should have its geometric center coincide with the geometric center of a spindle, usually driven by a motor. One condition which will prevent accurate centering is dirt or other contamination on the centerpiece or spindle.
Prior art mechanisms have used a cone to taper approach where the center hole in the disk is tapered to fit over the cone shaped spindle. This type of mechanism suffers from potential damage during insertion, since both the tapered disk surface and the cone are made of metal with no shock absorbing mechanism between them. It also suffers from dirt susceptibility, since the surfaces only touch when fully inserted, and there is no wiping effect to remove dirt or other contamination.
Another prior art mechanism is the use of a screw mounted in the center of the disk which is screwed into threads in the center of the spindle. While this mechanism solves the centering problem, it requires that the disk be manually mounted to the spindle from the top to allow the screw to be easily turned and so this mechanism is not useful then the disk must be inserted from the side of the disk storage device. Side mounting is the most common form used in the industry today.
Another prior art mechanism, disclosed in U.S. Pat. No. 4,166,622 is the use of compression cylinders mounted in indentations about the periphery of the center hole. This type of mechanism is expensive to manufacture since each cylinder is made separately and then assembled to the hub later.
Thus, there is need in the art for an improved centering mechanism for centering data storage disks on a spindle. The present invention addresses that need.